Relationship of clot burden and echocardiographic severity of right ventricular dysfunction after acute pulmonary embolism.

The impact of pulmonary embolism on right ventricular (RV) performance can be evaluated by echocardiography, however, the relationship between pulmonary vascular involvement and RV burden is controversial. To assess the effect of clot burden on RV performance we studied 85 patients (aged 53 ± 17 years, 39 female) with confirmed PE by multislice computed tomography (CT) and echocardiography within 24 h of diagnosis. A CT score ranging from 1 to 20 points according to the pulmonary arteries involved was used. RV function was evaluated with fractional area change (FAC), with dysfunction present when FAC < 40%. Tissue Doppler RV systolic (s') velocities and myocardial performance index (MPI) were obtained, as well as pulmonary artery pressure (PAP). Mean CT score was 9.4 ± 6.7. Only 31 out of 85 patients (37%) presented with RV dysfunction, with FAC measuring 27.8 ± 7.2% in patients with dysfunction compared to 47.8 ± 4.4 for those with preserved RV function (p < 0.05). RV dysfunction was associated to older age, higher CT scores, increased pulmonary pressures and MPI and decreased s' (p < 0.001). An inverse correlation with CT clot burden was found for FAC (r = -0.57), whereas a direct correlation was seen for PAP (r = 0.51) and MPI (0.32). No correlation was observed for tissue Doppler velocities. In patients with acute PE, the effect of clot burden on RV performance is better expressed FAC than tissue Doppler indexes; the increase in pulmonary pressure is proportional to the magnitude of obstruction.